What do you mean by sub netting? Explain with one example.

Question : What do you mean by subnetting? Explain with one example.

Ans:   

A subnetwork or subnet is a logical subdivision of an IP network. The practice of dividing a network into two or more networks is called subnetting.

Advantages of Subnetting: 

1. Improve network performance and speed:

A single broadcast packet sends out information that reaches every device connected to that network. 

Subnetting enables you to ensure that the information remains in the subnetted network or broadcast domain, which allows other subnets to maximize their speed and effectiveness.

2. Reduce network congestion:

Every computer would see broadcast packets from all the computers and servers on the network. This leads to increased congestion, reduced network performance, and slower response times.

Subnetting ensures that traffic destined for a device within a subnet stays in that subnet, which reduces congestion. 

3. Increasing the network security:

By splitting your network into subnets, you can control the flow of traffic using ACLs, QoS, or route-maps, enabling you to identify threats, close points of entry, and target your responses more easily.

Another option is to limit access to resources on wireless clients, ensuring that valuable information isn’t easily accessible in remote locations.

4. Control network growth:

Without subnetting there is a waste of thousands of IP Address. Subnetting allows you to create group as per your requirement. You can be more sure about the perfect utilization of all available hosts in your network.

5. Easy administration:

By subnetting, you can create networks as per your requirements. You can control easily all this logical group of networks. With careful planning and implementation, subnetted networks generally are easier to manage and troubleshoot.

Example of Subnetting: 

Divide the network 193.1.2.0 network with 2 subnetwork.

First thing, It is a class C IP so, there are 24 bits in the network id part and 8 bits in the host id part.

To divide a network into two ( 21=2 ) parts you need to choose one bit from host id part for each subnet i.e, (0,1).

For Subnet-1:

The first bit which is chosen from the subnetting bit  id part is zero.

So now range will:  193.1.2.00000000      (host all zero)

                                      193.1.2.01111111      (host all one)

Thus, the range of subnet-1: 193.1.2.0 to 193.1.2.127

For Subnet-2:

The first bit chosen from the subnetting bit id part is one.

So now range will: 193.1.2.100000000 

                                     193.1.2.11111111

Thus, the range of subnet-2: 193.1.2.128 to 193.1.2.255

And the subnet mask will be : 255.255.255.1000 0000        (subnetting bit 1 is added)

                                                          255.255.255.128

Kindly note that here in the subnet range first IP will be considered as a network IP address and last IP of that subnet range will be considered as a broadcast IP address.